Once more again, with feeling.. Fluke 8840A multimeter!

I've managed to acquire a very nice Fluke 8840A multimeter from eBay. This is a 5½ digit desktop multimeter with RMS AC and GPIB options installed. It seems to be fully functional.. except for the VFD display which is showing some signs of age and where the brightness is a bit uneven and somewhat dim.

Based on lessons learned from the Fluke 8050A project, I'll do things a bit differently this time around. Also, the nature of the Fluke 8840A meter is a bit different, and I'll necessarily need to adapt to that. I think this time around, I'll use an STM32F407 based board with more I/O pins. The board is a bit larger, but I don't think that space is an issue. The cost is a bit higher, probably $15 vs. $5 for the STM32F103 “Maple Mini” cloned I used before, but there are lots more I/O pins available, and more importantly, more 5 volt tolerant pins. Also, additional peripherals will be available such as UART, SPI and I2C (and the pins to use these.)

This opens up some other options, such as including a Wi-Fi or other communications options, data logging capabilities (the STM32F407 boards have a microSD card slot available, not to mention a bunch more RAM. Maybe an audio annunciator? Who knows?